A Tunnel Concentrator is a configured connection point for use with the Generic Routing Encapsulation (GRE) point-to-point tunnel. Configure the name and IP address for each Tunnel Concentrator, then specify one to three concentrators in the GRE topology definition. The Tunnel Concentrator IP address (tunnel termination point) is specified in the VLAN definition. The VLAN specification in the configuration Profile (that is associated with the device group) determines the connection between the Tunnel Concentrator IPv4 address and the AP.